Researchers from the China Rural Health Initiative (CRHI), who were behind the programme, say the results will likely have an impact on public health policymaking in China and in other countries.
“Centrally implemented, population-based approaches to salt reduction have been identified by the WHO and other groups as among the most cost-effective possible strategies for vascular disease prevention in both developed and developing countries,” said Dr Nicole Li, a research fellow at The George Institute, which is one of the institutions behind the CRHI.
“We identified a low-cost, highly practical intervention that was effective in reducing population sodium intake [in China].”
The study took place in 120 rural villages across five northern Chinese provinces over 18 months. The location was chosen for the high average daily sodium intake of its population which, at 4.7g to 5.9g is far in excess of the current recommendation from the World Health Organisation of 2g per day. As a result, residents there are exposed to a higher risk of stroke and other vascular diseases.
Half of the villages were selected to receive no intervention, whereas the remaining villages received community-based health education that advised lower sodium intake, with special messages for residents at high risk of cardiovascular disease.
In addition, a low-sodium salt substitute was promoted through a health education programme and in village convenience stores. These 60 villages were further divided at random with 30 receiving a price subsidy for the salt substitute, and 30 getting the substitute at full price, which is about twice that of regular salt.
Daily urine samples of 20 people from each village for sodium and potassium intake were examined after the intervention, with villages with price-subsidised salt substitutes showing a reduced daily sodium intake of about 1g of salt compared to non-intervention villages.
Moreover, there was an increase in daily potassium intake across all villages with intervention, and a greater consumption in villages with price-subsidised salt substitutes.
Professor Yangfeng Wu, director of The George Institute for Global Health at Peking University Health Science Centre, indicated that the study findings will certainly be relevant to public health policy making in the future.
“Population sodium intake was effectively reduced by our intervention, primarily through increased use of a salt substitute. It also suggests how the community can be engaged in tackling and ‘owning’ a major health issue,” Wu said.
“Larger effects could be achieved in rural China by a wholesale switch from salt to salt substitute, with the potential for major public health benefit in this population at high risk of stroke. ”